MAINTAINERS: Update BNXT entry with firmware files

There appears to be a maintainer gap for BNXT TEE firmware files which
causes some patches to be missed. Update the entry for the BNXT Ethernet
controller with its companion firmware files.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20220427163606.126154-1-f.fainelli@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: ffainelli

MAINTAINERS

@@ -3913,7 +3913,9 @@ BROADCOM BNXT_EN 50 GIGABIT ETHERNET DRIVER
 M:	Michael Chan <michael.chan@broadcom.com>
 L:	netdev@vger.kernel.org
 S:	Supported
+F:	drivers/firmware/broadcom/tee_bnxt_fw.c
 F:	drivers/net/ethernet/broadcom/bnxt/
+F:	include/linux/firmware/broadcom/tee_bnxt_fw.h
 
 BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER
 M:	Arend van Spriel <aspriel@gmail.com>